1. Field of the Invention
The present invention relates to accelerometers and more particularly to multi-mode linear lasers employing proper mode sizing to a proof-mass-mirror within an accelerometer.
2. Description of the Prior Art
The sensitivity of a basic accelerometer is limited by the proof mass relationship to the force to be sensed; i.e. F=ma or a=F/m. The smallest acceleration that can be sensed is dependent on the proof mass, m and the (restoring) forces acting upon it. It is clear that for a fixed proof mass m, smaller accelerations to be sensed require either: (1) smaller forces or (2) greater resolution of proof mass displacement. If the proof mass is suspended by a simple spring then the displacement is related to the forces acting upon it by F=-kx. Smaller spring force creates a problem in dynamic range and or size of the spring. Greater resolution can be obtained with the use of a resonant cavity or active laser.
Also, the use of digital computers in advanced navigation and guidance systems to calculate velocity and position require an accelerometer whose output is inherently digital.
It is an object of the present invention to obtain increased resolution of the motion of the proof mass in a fashion that produces digital counts for modem inertial navigation systems.